[The Inhalation Toxicity of Tertiary Butylisonitril in Rats and Mice. Acute Toxicity and Evaluation of Embryotoxic and Mutagenic Effects (author's Transl)]

The inhalation toxicity of tertiary butylisonitril (TBIN) was evaluated in rats and mice. In addition, pregnant rats were exposed to TBIN aerosols to test its embryotoxic effects and male mice were exposed to TBIN aerosols to evaluate its mutagenic effects using the dominant lethal test. Inhalation of TBIN aerosols caused death in rats only at high concentrations. The following inhalation LC50 values were determined for rats and mice following inhalation of TBIN aerosols: 4-hr exposure: male rats 715, female rats 710, male mice 377; five 4-hr exposures: male and female rats between 356 and 583 mg/m-3 air. The animals were impaired for a long period of time, and death occurred up to 10 days after the exposure. Female rats were exposed to TBIN aerosols from the 6th to the 15th day of gestation daily for 4 hrs. The used concentrations were not toxic to the pregnant rats. It became evident that only the lowest concentration (14 mg/m-3) was not effective to the development of the fetus. A TBIN concentration of 36 mg/m-3 definetely increased the resorption in embryos, and with 71 mg/m-3 a complete loss of the fetus occurred due to resorption. A teratogenic effect could not be determined. A single 4-hr inhalation of 125 mg TBIN/m-3 air caused changes of the sperms of male mice. There was a decreased fertilization capability during the first week of mating after the exposure and a decreased implantation rate with a simultaneous increase of pre-implantation losses in the females. With respect to industrial hygiene it is important that concentrations of TBIN in the air show embryotoxic and anti-spermatogenic effects in animals, which they tolerated without symptoms of poisoning.